Loud speaker



D SPEAKER 2 Sheets-Sheet 1 Aug. 25, 1931.

Filed Feb. 20, 1951 INVENTOR.

RAY TOLERT y BY 2 Q Aug. 25, 1931. R. E. TOLERTON 1,820,585

LOUD SPEAKER Filed Feb. 20, 1951 2 Sheets-Sheep 2' INVENTOR. RA): E. TOLERTON.

Patented Aug. 25, 1931 RAY E. TOLERTON, OF FORT WAYNE,

INDIANA, ASSIGNOR TO THE MAGNAVOX COMPANY, OF CHICAGO, ILLINOIS, A CORPORATION OF ARIZONA LOUD SPEAKER Application filed February 20, 1931. Serial No. 517,335.

My present invention relates to sound re-' producing apparatus and more particularly to such apparatus wherein an open ended conic-a1 diaphragm is employed.

An object of my invention is to provide a new and novel construction for sound reproducing apparatus which will greatly simplify and reduce the cost of assembling.

Another object of my invention is topro- 1o vide a new and improved type of diaphragm housing which will not only function to support the diaphragm but also serve to align thehelectromagnetic actuating means therewit A further object of my invention is to provide a new and improved protective housing for a conical diaphragm having two parts which when secured together will clamp the rim of the diaphragm. and support it centrally in a fixed position with respect to the diaphragm actuating means.

Another object of my invention is to provide a loud speaker construction wherein the diaphragm housing, the diaphragm and the electromagnetic field structure may be conveniently assembled and secured together in a simple manner. p

In the past when constructing sound re-. producing apparatusof the type contemplated by my invention it has been the practice to secure the parts of the magnetic field structure together with respect to each' other by suitable means and then, secure the diaphragm 'supporting housing upon this as- 85 sembly by other means. The diaphragm was then mounted at its rim upon the diaphragm housing by a series of arcuate clamping plates which required from eight to twelve screws. Y I

In accordance with one aspect of my invention I propose to simplify the aboveassembly by providing a diaphragm housing which will serve to hold the parts of the magnetie field structure in proper operative relation to each other. In connection with the-1 id an diaphragm housing I also provide a diaa" phragm securing member that engages the diaphragm at its periphery and which is se- 0 cured in place by means extending fromthe electromagnetic field structure through the center of the diaphragm.

For a better understanding of my invention reference should be had to the accompanying drawings wherein I have shown by wa of illustration and not of limitation apparatus embodying my invention.-

In these drawings wherein like numerals refer to like views, k

Figure 1 is a plan view in section taken along the horizontal center line of a loud speaker of the moving coil type,

Figure 2 is a partial front elevation of the speaker shown in Figure 1,,

Figure 3 is an enlarged fragmentary sec tional view showing a portion of the speaker illustrated in Figure 1, with flange turned out for mounting in a baffle, 1

Figure 4 is a fragmentary sectional view showing a modified form of securing means ior my improved diaphragm securing memer, Figure 5 is a fragmentary vertical elevation, half in section showing a modified form of my invention,

Figure 6 is a front view in elevation of parts throughout the several the diaphragm actuating coil centering means with its support, and

Figure 7 is a front view of one ofthe supports shown .in Figure 6.

In Figures 1, 2 and 3 of the drawings I have shown my invention as embodied in a loud speaker for reproducing phonograph and radio music. vThe loud speaker here illustrated is of the electrodynamic type. The magnetic field producing structure has a pot or magnetic frame 10 in which there is secured/a centrally and axially extending core 11. A magnetizing coil 12- for energizing the field is disposed about the core 11.

Cooperating with the core 11 and closing the magnetic frame 10 there is provided an annular pole piece 13. This pole piece has an opening at its center of suflicient diameter gap fora diaphragm actuating coil. As here shown, the annular pole piece 13 carries a spacing or centering ring 14 of non-magnetic material which will serve to maintain the above referred to air gap uniform throughout its circumference. The diaphragm actuating coil designated by the numeral 15 is shown as attached to the apex of a truncated conical diaphragm 16.

Adjustably secured upon the annular pole piece 13, as will hereinafter appear, there is provided a flexible centering means for maintaining the coil 15 centrally within the air gap of the magnetic field structure. means comprises a supporting member it upon which there is mounted a flexible centering device 18 that engages the apex of the dia hragm at the point where the coil 15 is attac ed thereto. The centering device 18 is of such construction that it Wlll prevent any lateral movementoi the coil 15 in the air gap and at the same time will not interfere with a proper axial movement of the coil.

The rim of the diaphragm 16 is shown as supported by a housing 19 which extends backwardly therefrom to a point where it engages the magnetic field structure. At this point the housing 19 is provided with a reentrant flange portion 20 which engages both the frame member 10 and the annular pole piece 13 so as to hold these two latter members in proper alignment.

Disposed in front of the diaphragm I provide a plate like securing member 21. This member 21 has an annular rim 22 which is adapted to engage and hold the rim of the diaphragm 16 in clamped engagement with the housing 19. The member 21 is also provided with a central inwardly projecting portion, here shown as comprising radia arms-23 which terminate and form a hub 24. As illustrated, the member 21 is held in clamped engagement with the diaphragm 16 and the housing 19 by means of a nut 25 which is threaded upon a projection 26 carried by the core 11.. A washer 27 ot suitable non-magnetic material is shown as disposed beneath the nut 25 for the purpose oi" interrupting any ma ietic circuit should the housing 19 and t" e member 21 be made of magnetic material. lhe rim of the housing 19 has a flange 28 extending there around which in conjunction with the member 21 forms an annular recess tor the reception of a sound or vibration damping packing 29. The packing 29 may be oi any suitable material, such a felt or the like, and is adapted to engage with a bafile or cabinet wall when the loud speaker is in use. 7 From the above it will be seen that when the nut 25 is turned up on the projection 26 of the core 11 the several component parts of the speaker will be held firmly together in proper operative relation with each other without any other securing means.

In Figure at of the drawlngs 1 have illustrated a modified arrangement for securing the parts together. In this instance, instea of forming a projection upon the core 11, it

show the core as internally threaded for the T his.

l ber 21 ea set reception of a securing screw 30. When this latter arrangement is used the screw 30 will be made of brass or other non-magnetic material so as to more eiiectively prevent the formation of any leakage or shunt paths for the magnetic flux which should flow across the air gap of the field structure.

In the embodiment of my invention illustrated in Figure 5, I show the magnetic field frame or pot 10 as having oppositely disposed outwardly extending flanges 31 between which the pot is cut away to provide for a circulation of cooling air about the coil 12. This type ot pot or frame member may be formed by pressing the pot from stock having a width less than that of the die of the pressing machine. in this showing the annular pole piece 13 is enlarged sufliciently to make a good magnetic contact with the flanges 31 and is provided with recesses 32 into which projections 33 carried by the flanges 31 may project for the purpose of holding the parts in alignment. 1

lhe diaphragm supporting housing here designated by the numeral 34 is shown as having a simple flange 35 which abuts with the surface of the annular pole piece 13. In other respects this housing is similar to the one shown in Figures 1, 2 and 3 of the drawings.

It further diiierence in the construction here illustrated is that the projection 26 upon the core 11 is shortened so that it does not approach as near to the clamping plate or memas in the construction of Figure 1. Because of this difference in the length of the projection upon the core 11, 1 provide a special form of nut or securing member 36. The member 36. like the screw 30 projects through the hub 24 of the member 21 and is preferably made of brass or other non magnetic material.

'lo properly center the diaphragm actuating coil in the air gap of the magnetic field and'hold the provide a flexible centering means which when positioned and secured upon the magnetic field structure will serve to hold the diaphragm 16 and its coil 15 in operative relation'to the magnetic field. lhis centering means is illustrated in Figures 6 and 'Z' of the drawing as comprising a suitable supporting member 3'? and a flexible device 38. As shown in Figure 5, the supporting member 37 is adapted to surface of the annular pole piece 13 by three screws 39. lln order that the supporting member 37 may be easily adjusted upon the pole piece for the purpose of centering the coil 15, 1 project the screws 39 through relatively large holes 40 in the pole piece 13 so that the screws will have some freedom of movement. The member sitely disposed raised portions 11 upon which the specially formed flexible centering dediaphragm in position l be secured upon the front 37 has two oppovice 38 is secured. After the coil 15 has been properly centered the screws 39 are tightened and the coil and its centering device will then be held firmly in place.v

The flexible centering device 38 is preferably assembled with the'diaphragm 16 at the time the actuating coil 15 is aifixed thereto and is glued or otherwise secured firmly upon the diaphragm. As illustrated the centering device 38 has a central ring portion 42 which engages with the diaphragm 16 and its coil 15 at the point where these parts are secured together. This ring portion 42 is rendered movable with respect to the support 37 by virtue of a plurality' of radial arms 43 which double back upon each other when they engage the raised portions 41 on the support 37 The ring portion 42 of the device 38 is also provided with cars 44 that carry suitable terminals to which the ends of the coil 15 and the lead out wires, not shown, maybe soldered.

In a further modified form of my invention I may dispense with the member 37 that supports the flexible device 38, and mount this. latter device directly upon the diaphragm housing 19 or 34. In this latter event suitable inwardly extending brackets or cars will be formed upon the diaphragm housing in a plane corresponding to the location of the device 38. With this type of mounting for the flexible device 38 I will preferably provide means for centering the diaphragm housing with respect to the annu lar air gap as shown, for instance, in Figure 1.

Reproducers of the type here illustrated are usually mounted upon a suitable bafile which serves to prevent interference between the sound waves produced on opposite sides of the diaphragm 16. This baflle may be a simple plane surface 45 having a hole 46 therein of a diameter corresponding to the size of the speaker. The general practice is to secure the reproducer upon the back of the baflle and provide the hole 46 with an ornamental grille behind which a piece of silk or other 'fabric is placed. This conceals the reproducer and otherwise improves the appearance of the apparatus.

By referring to Figure 3 of the drawings, it will be noted that I have modified the hous ing 19 by turning the flange 28 outwardly so that it will overlap and in effect frame the bafile hole 46. With this type of housing it will be possible to eliminate the usual baflle grille as the member 21 of my improved reproducer may be ornamented and if desired provided with a silk backing. Such a structure will eliminate the necessity for expensive grille work upon the cabinets and/or bafiie and will also greatly improve the whole general assembly.

From the above it will be seen that I have produced a loud speaker construction which embodies features not heretofore obtained in similar devices and in which the number of parts required have been greatly reduced and the operations of assembling simplified.

While I have, for the sake of clearness and in order to disclose my invention so that the same can be readily understood, described and illustrated specific devices and arrangements, I desire to have it understood that this invention is not limited to the specific means disclosed but may be embodied in other ways that will suggest themselves, in view of this ture having a central pole and an outer annular pole forming an annular airgap for the diaphragm actuating coil, a flexible support for the apex of said diaphragm, an outwardly extending support for the rim of the diaphragm, a plate adapted to cooperate with said last support and clamp the rim of the diaphragm in a fixed position, and means extending from said plate through the diaphragm cooperating with the inner pole of the magnetic field structure for holding the parts together.

2. In sound reproducing apparatus of the type having a conical diaphragm and attached actuating coil, the combination of an open ended conical diaphragm, a magnetic field structure having a central pole and an outer annular pole forming an annular air gap for the diaphragm coil, an outwardly extending support for the rim of the diaphragm, a plate adapted to cooperate with said last support and clamp the rim of the diaphragm in a fixed position, and means extending through the diaphragm cooperating with said plate and the inner pole of the magnetic field structure for holding the parts in clamped engagementwith each other.

3. In sound reproducing apparatus of the type having an open ended conical diaphragm, the combinationof an open ended conical diaphragm, an electromagnetic field around the diaphragm netic field structure and center for holding the parts in clamped engagement with each other. i

i. In sound reproducing apparatus of the type having a conical diaphragm, the combination of an open ended conical diaphragm, an electromagnetic field structure having a central pole and an outer annular pole torming an annular air gap for a diaphragm actuating coil, an adjustable flexible support upon said magnetic field'structure for centering the apex of said diaphragm with respect to said air gap, an outwardly extending support for the rim of the diaphragm having means for centering said rim with respect to said air gap, a plate adapted to cooperate with said last support and clamp the rim ot the diaphragm in a fixed position, and means extending through the diaphragm cooperating with the inner pole of the magnetic field structure for holding the parts together.

5. A protective housing and support for conical sound reproducing diaphragms, comprising a conical diaphragm, a magnetic field structure, an outwardly dared member secured to said field structure and disposed adapted to engage and support the rim thereof, said member having means adapted to engage the magit with respect to the latter, and means secured to the magnetic field structure for clamping the rim of the diaphragm upon said outwardly flared member.

6. A protective housing and support for a conical sound reproducing diaphragm, comprising a magnetic field structure two out wardly flared members disposed on opposite sides of the diaphragm and adapted to clamp and support the rim thereof, the outer one of said members having means for engaging and centrally supporting the magnetic field structure, and means carried hy said magnetic field structure adapted to engage the inner one of said members and hold said members and said magnetic field structure in clamped engagement with each other.

7. In a loud speaker ot the moving coil type, the combination of a cylindrical magnetic field structure comprising a pot lilre member having a fined inner pole and a removable annularpole, a diaphragm adapted to cooperate with said field structure, and a supporting housing for said diaphragm hav-' ing a reentrant liange at one end adapted to receive and align said cylindrical pot and said annular pole piece with respect to each other and said diaphragm;

' 8. In a loud speaker of the moving coil. type, the combination of a cylindrical magnetic field structure member having a fixed central pole and a removable annular pole, a diaphragm supporting housing having a reentrant ilange at one end adapted to receive and align said cylindrical pot and said annular pohpiece, a

comprising a pot lilre' insures conical diaphragm having a coil at its apex disposed in the air gap formed by said fixed pole and said annular pole piece, a second supporting member; tor said diaphragm adapted to engage the rim of said diaphragm and hold it in clamped engagement with said diaphragm supporting housing, and means extending through the coil upon said diaphra m adapted to hold said last member, said ousingand said magnetic field structure in clamped and axial alignment.

9. lln a loud speaker of the moving coil type, the combination of a magnetic field structure having an annular air gap, a diaphragm supporting housing having a reentrant flange at one end adapted to center said field structure with respect thereto, a conical diaphragm having a coil at its apex disposed in the air gap of said field structure, a second supporting member for said diaphragm adapted to engage the rim of said diaphragm and hold it in clamped engagement with said supporting housing, and means extending through the coil upon said diaphragm adapted to hold said last member, said housing and said magnetic field structure in clamped and axial alignment.

ll). lln a loud speaker or? the moving coil type, the combination of an electromagnetic field structure having an annular air gap, a conical diaphragm having an actuating coil disposed in said air gap, a support for holding the periphery of said diaphragm in spaced relation. with said electromagnetic field structure, and a securing means for clamping the periphery of said diaphragm upon said support comprising a member having an outer portion adapted to engage the diaphragm at its periphery and a central portion adapted to be secured to said magnetic field structure by meansextending through the coil upon said diaphragm,

A protective housing and support for a conical sound reproducing diaphragm, comprising an open ended conical diaphragm, two i ing means -ilor mounting same upon a hams 1 and the inner one oil said members being "formed to cooperate with said outer member to provide a protective grille at the front of the diaphragm, and means extending through the center oil said diaphragm for securing said inner and outer members in clamping engagement with the rim of the diaphragm.

l2, A protective housing and support for a conical sound reproducing diaphragm comprising an open ended conical diaphragm, a

diaphragm supporting housing, a magnetic field structure secured to said housing, a

shoulder at the rim of said housing for supporting the rim of said diap wardly extending flange hragm, an outad acent the shoultilt Elm)

- der upon said housing for mounting same upon a baflie, a front plate adapted to cooperate with said housing and provide a protective grille at the front of the diaphragm, and

means extending through the opening in said diaphragm for securing the front plate in position.

13. A protective housing and support for a conical sound reproducing diaphragm comprising an open ended conical diaphragm, a diaphragm supporting housing, a shoulder at the rim of said housing for supporting the rim of said diaphragm, an outwardlyextending" flange adjacent the shoulder upon said housing for mounting same upon a bafiie, a front plate adapted to cooperate with said housing to clamp and support the rim of the diaphragm and provide a protective grille at the front of the diaphragm, and means ex tending through the moving portion of said diaphragm for securing the front plate upon said housing.

RAY E. TOLERTON. 

